It is known from EP0757529B1 to provide a cooking device comprising a container for receiving food which has a heater integrally formed with a base of the container. The integral container and heater are disposed on a main body. The heater is integrally formed with the base of the container so that heat emitted by the heater is directly transmitted to the food in the container. This arrangement results in a short heat up time and cooking time.
In an alternative configuration, the heater is provided separate to the container such that a gap is formed therebetween. The heater is integrally formed with the main body of the cooking device and the container is stood on the heater. However, a disadvantage of this arrangement is that the heat up time and the cooking time are increased due to the indirect transfer of heat emitted from the heater to the food to be cooked disposed in the container.
It is also known that heating devices such as slow cookers, yoghurt makers and other domestic appliances include a heater element, typically electrically driven, with a temperature sensor in intimate thermal contact with the element to detect its operating temperature. The temperature sensor provides a temperature signal as a function of the heater element temperature, and a control processor that is responsive to the temperature signal controls the operational temperature of the heater by controlling an electrical drive current fed to the heater from e.g. a mains supply. The control processor may include a user interface which allows the user to set the desired operating temperature so that the control processor can compare the temperature signal from the temperature sensor with the set temperature and control the heater drive current in a feedback loop.
A problem with this known arrangement is that if the temperature sensor is in an unsatisfactory, non-intimate thermal contact with the heater element, the temperature sensor will under-record the operating temperature of the heater element, which can result in over-heating of the device that could result in a fire, melting of the appliance or the release of poisonous smoke, particularly when the heating device is configured for use over long periods e.g. overnight, such as a slow cooker or a yoghurt maker.